Domain A is first.mylocation.com - 2003 domain with 2003 Functional level
Domain B is second.mylocation.com - 2008 domain with 2008 Functional level
Domain A has an Exchange 2003 server in it that both domains use. Currently we have DNS set up in both domains. If we use the Domain A DNS, all is well. If we use the Domain B DNS, Outlook loses connection with Exchange shortly thereafter. I am trying to determine if I just have a simple DNS set incorrect (the host mail.mylocation.com is added and Exchange is using SSL certificate with same name internal and external). I know I am probably short on info here, but can supply responses to any questions.